182 PRACTICAL ORGANIC CHEMISTRY It consists of an oblong Lothar-Meyer air-bath about 60 cms. (241115.) long and 15 cms. ( 6 ins.) wide. It is heated on each side by a series of small gas jets made by perforating an iron pipe which runs below the air-bath. The hot air passes up the space between the outside metal casing and an inner rectangular metal box, and then clown and into the interior of the air-bath through a number of round holes at the bottom of a central v ! V <--------------60 cm.-------------•> FIG. 79. rectangular chamber, and finally escapes through a series of holes in top of the outer cover. The air-bath is perforated. at both ends so as to admit a piece of wi'de glass tubing. This tubing (1*5—2 cms. diam.) is of such a length that it projects about 2—3 cms. at one end and 5-6 cms. at the other, the latter being bent and connected to a receiver. The shorter end is attached by a cork to a small distilling flask through which, a. current of dry hydrogen is passed from a Kipp by a delivery tube, which reaches to the bottom of the flask.